1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) devices, and more particularly, to a test device used in liquid crystal display (LCD) panels and an associated system.
2. Description of the Prior Art
Two principal methods of discharge—air discharge and contact discharge—are applied to thin film transistor-liquid crystal display (TFT-LCD) panels on which reliability testing is conducted. Referring to FIG. 1, electro-static discharge (ESD) testing at a voltage range of 0 to 4 KV is conducted on test points 1 to 8.
In an actual application, test points 3 to 8 can pass the ESD testing successfully while test points 1 and 2 cannot. When the amount of voltage is excessive during the ESD testing is conducted on test points 1 and 2, horizontal or vertical bright lines will occur easily. Analysis reveals that switching circuits under a driver chip 11 of the LCD panel (referring to FIG. 1B) is damaged, which leads to irregular transmissions of signals.
Referring to FIG. 1B, FIG. 1B shows an internal structure diagram in FIG. 1A. A test solder pad 12 is disposed near test points 1 and 2 (referring to FIG. 1A). When the ESD testing is conducted on test points 1 and 2, electric current flows inside the LCD panel through a test line 13 connected to the test solder pad 12. The electric current flowing inside the LCD panel causes damage to the circuits inside the LCD panel, which is the primary reason why the switching circuits are damaged.
In sum, an excessive amount of electric current occurring during the voltage testing is conducted on LCD panels usually causes damage to the circuits inside the LCD panels in the conventional technology. This problem needs to be solved by LCD manufacturers.